Process and apparatus for the reversible adsorbtion of carbon dioxide

ABSTRACT

An apparatus ( 10, 110, 210, 310 ) for the separation and recovery of CO 2 , from air, by a cyclic adsorption/desorption process using a loose particulate sorbent for gas adsorption. The apparatus has a plurality of adjacent, parallel, spaced-apart layers ( 24, 124, 224, 324 ), each having a stiff frame supporting a flexible, gas-permeable fabric enclosure for the sorbent. The gas inlet ( 14, 114, 214, 314 ) and outlet ( 18, 118, 216, 316 ) of the apparatus are on its axially opposite sides, and each layer ( 24, 124, 224, 324 ) extending axially within the apparatus. The recovered CO 2  can be either supplied to an enclosed space, recycled to an enclosed space, from which the CO 2  had been separated, or vented to the exterior of the latter enclosed space.

TECHNICAL FIELD

This invention relates to a process and apparatus for separating andoptionally recovering a gaseous component (e.g., CO₂) from a gas stream,such atmospheric or outdoor air or air inside an enclosed space such asin a building, e.g., in one or more rooms of a house or office buildingor in a greenhouse, or in a vehicle, e.g., a car, ship, truck, airplaneor bus, or an exhaust gas from a chemical (e.g., combustion) and/orbiological process. This invention particularly relates to a process andapparatus for separating and optionally recovering CO₂ from air bydiffusion of air through an amine-containing particulate substrate whichcan be processed to selectively adsorb and subsequently desorb CO₂. Thisinvention also particularly relates to a process and apparatus forseparating and removing CO₂ from outdoor air or air in an enclosedspace, e.g., in a greenhouse or a car, and then either providing thatCO₂ to the enclosed space or venting that CO₂ to the outdoors.

BACKGROUND OF THE INVENTION

Gas separation by adsorption on a suitable chemical substrate has manyapplications in industry, for example for removing and optionallyrecovering a specific component from a gas stream, where the desiredproduct can either be the component removed from the gas stream, theremaining depleted gas stream, or both. Thereby, trace components aswell as major components of the gas stream can be targeted by theadsorption process. One important gas separation process involvescapturing carbon dioxide (CO₂) from gas streams, e.g., from flue gases,exhaust gases, industrial waste gases, or atmospheric air. WO2010.027929A1 and WO2010/151271A1 describe porous monolithic structures containingan amine for reversible adsorption and separation of CO₂ from acombustion process gas stream. WO2010/091831 A1 describes fabrics offiber filaments containing an amine for the reversible adsorption anddesorption and subsequent recovery of CO₂ from the atmosphere.WO2012/188346 A1 describes a porous matrix of amine functionalizedcellulose nanofibers for the reversible adsorption and desorption of CO₂from a gas stream. WO2014/170184 describes a process and apparatus forthe reversible adsorption and desorption and subsequent recovery of CO₂from a gas stream, using a loose amine-containing particulate sorbentbed. The sorbent is held in a stack of parallel, spaced apart,self-supporting layers or cartridges, each cartridge extending parallelto the gas stream. Each cartridge has two sheets of a flexible, gaspermeable fabric that are mounted on a stiff frame and that form acavity enclosing the sorbent. During adsorption, the incoming gas streamis forced, under ambient conditions, under pressure, to flow through asheet forming an inlet face of each cartridge, through the sorbentmaterial in the cavity of the cartridge, and subsequently through asecond sheet forming an outlet face of each cartridge. Duringdesorption, the sorbent is heated and subjected to a vacuum.

WO2016/037068 A1 also describes a process and apparatus for thereversible adsorption and desorption and subsequent recovery of CO₂ froma gas stream, using a loose amine-containing particulate sorbent bed.The sorbent is held in a stack of parallel, spaced apart,self-supporting layers or cartridges, each cartridge extendingperpendicular to the gas stream. Each cartridge has two sheets of aflexible, gas permeable fabric that are mounted on a stiff frame andthat form a cavity enclosing the sorbent. The gas stream diffusesthrough a sheet forming an inlet face of each cartridge, through thesorbent material in the cavity of the cartridge, and subsequentlythrough a second sheet forming an outlet face of each cartridge.

SUMMARY OF THE INVENTION

In accordance with this invention, a process and apparatus are providedfor the reversible adsorption and desorption and subsequent recovery ofa gaseous component, particularly CO₂, of a gas stream, particularlyair, from the remainder of the gas stream, using a loose particulatesorbent, advantageously an amine-containing sorbent. The sorbent is heldin one or more, parallel stacks of cartridges or layers, each stackcontaining a plurality of adjacent, parallel, spaced-apart cartridgesand each cartridge extending substantially parallel to the gas stream.Each cartridge has a flexible, gas permeable fabric enclosure that ismounted on a stiff frame and that forms a cavity within the frameenclosing a certain amount of the sorbent. During adsorption of thegaseous component, the gas stream diffuses into the cavity of eachcartridge through its fabric enclosure, then through the sorbent in thecavity of the cartridge, and then out of the cavity of the cartridgethrough its fabric enclosure. The invention features specific structuresof each cartridge and its cavity containing its sorbent that provide areversible adsorption of the gaseous component with a very low pressuredrop of the gas stream and with a very high mass transfer rate betweenthe gas phase and the surface of the sorbent.

The process and apparatus of this invention for a cyclicadsorption/desorption of a gaseous component of a gas stream utilize oneor more, preferably a plurality of, more preferably two, parallel stacksof cartridges. Each cartridge includes a flexible fabric enclosure whichholds a quantity of sorbent and is gas permeable but impermeable to thesorbent. The stiff frame of each enclosure holds the cartridges spacedapart and in a self-supporting way in a sealable enclosure. An inlet andan outlet for the gas stream are provided on opposite sides of thesealable enclosure and on opposite sides of the stack(s) of cartridges,so that each cartridge extends parallel to the path of the gas streambetween the inlet and outlet. The gas stream passes between thecartridges and diffuses through them and through their contents ofsorbent as it moves between the inlet and outlet, advantageously along aserpentine flow path. The diffusion of the gas stream along a serpentineflow path provides a very low pressure drop system which does notrequire pumping of the gas stream.

Advantageously, the sealable enclosure comprises a rigid vacuum chamber,to which the inlet and outlet of the gas stream are connected.Advantageously, the cartridges are separated from each other by 0.3-0.7cm, especially 0.4-4 cm.

Advantageously, at least 10, more advantageously at least 20, still moreadvantageously at least 25-40, cartridges are provided between the inletand outlet of the gas stream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 show a sealable enclosure with a rigid vacuum chamber of thisinvention. Sealable inlet and outlet valves are mounted on oppositeaxial ends of the vacuum chamber.

FIG. 4 shows the sealable enclosure of FIG. 1-3 (with the top wall ofits vacuum chamber removed), containing two laterally-extending, axiallyspaced-apart, parallel stacks of axially- and vertically-extending,laterally spaced-apart, parallel cartridges or layers. Each stackcontains a plurality of adjacent, parallel, laterally spaced-apartcartridges, and each cartridge encloses a measured amount of aparticulate sorbent for a gaseous component (e.g., CO₂) of a gas stream(e.g., air) in accordance with this invention.

FIG. 5 is a perspective view of a single empty cartridge of thisinvention, adapted to be filled with and hold a measured amount of thesorbent (not shown) for the gaseous component in accordance with thisinvention. The cartridge features a rigid frame, which can hold the top,bottom and axial sides of a fabric (not shown), enclosing the measuredamount of the sorbent. The frame is constructed from two frame membersadapted to enclose and hold the fabric enclosure for the sorbent.

FIG. 6 is a plan view of a frame member of the frame of the cartridge ofFIG. 5, containing a flat heating element extending substantially thefull width and length of the cartridge.

FIG. 7 is a sectional view, taken axially along the middle of the vacuumchamber of the sealable enclosure as shown in FIG. 3, showing cartridgesin two parallel stacks of parallel cartridges of this invention, adaptedto be filled with and hold measured amounts of the sorbent (not shown)in accordance with this invention.

FIG. 8 is a top plan view of the open vacuum chamber as shown in FIG. 4and showing its two laterally-extending, axially spaced-apart, parallelstacks of axially- and vertically-extending, laterally spaced-apart,parallel cartridges.

FIG. 9 is a simplified top view of the open vacuum chamber, like FIG. 8,showing (with arrows) a preferred flow of a gas stream axially throughthe vacuum chamber between its inlet and outlet and between the stacksof cartridges of this invention, so as to maximize the diffusion of thegas stream through the sorbent in the cartridges. Baffles are providedin the vacuum chamber for directing the flow of gas in a preferredserpentine flow pattern.

FIGS. 10A and 108 shows schematically the use of an alternative sealableenclosure 110 of this invention for removing CO₂ from outdoor air andproviding the removed CO₂ to an enclosed or confined, interior space,such as of a greenhouse.

FIGS. 11A and 11B shows schematically the use of another alternativesealable enclosure 210 of this invention for removing CO₂ from anenclosed or confined, interior space, particularly of an apartment in aresidential building, an office in a commercial office building, a car,a truck, a ship, an airplane or a bus.

FIGS. 12A and 12B shows schematically the use of another alternativesealable enclosure 310 of this invention for removing CO₂ from anenclosed or confined, interior space, particularly of an apartment in aresidential building, an office in a commercial office building, a car,a truck, a ship, an airplane or a bus.

DETAILED DESCRIPTION OF THE INVENTION

Shown in the Figures are preferred sealable enclosures of this inventionfor a process of: i) separating a desired gaseous component,particularly CO₂, of a gas stream, particularly air, from the remainderof the gas stream, using a loose particulate sorbent (not shown) for thedesired gaseous component, preferably a sorbent to which the desiredgaseous component will adhere in much more significant amounts than willother components of the gas stream, more preferably an amine-containingsorbent; and ii) subsequently recovering the desired gaseous component.During adsorption of the gaseous component, the gas stream diffuses intothe cavity of each cartridge through its fabric enclosure, then throughthe sorbent in the cavity of the cartridge, and then out of the cavityof the cartridge through its fabric enclosure.

The sealable enclosure holds a plurality of parallel, spaced apart,self-supporting cartridges, each cartridge extending substantiallyparallel to the gas stream through the enclosure. Each cartridge has acavity, within it, that can hold a measured quantity of the sorbent. Forthis purpose, the sorbent can be enclosed in a fabric material (notshown) which is gas permeable but impermeable to the sorbent and canform the lateral sides of each cartridge. The top, bottom and axialedges of this fabric enclosure can be held in a rigid plastic frameforming the top, bottom and axial sides of each cartridge. The fabricenclosure can comprise a fabric pouch or a single sheet of fabric,folded at the bottom of the cartridge, or two substantially parallelsheets of fabric, forming the lateral sides of the cavity of thecartridge that holds the sorbent.

The sorbent can be any conventional sorbent, to which the desiredgaseous component will preferentially adhere (relative to other gaseouscomponents of the gas stream) but which can be recovered from thesorbent, preferably using mild conditions. The sorbent is preferablyadapted to adsorb preferentially the desire gaseous component underambient conditions, e.g., at 20-40° C., and at 0.7 to 1.3 bar absolutepressure, and subsequently to be regenerated under mild conditions,preferably by being heated, e.g., up to 50 to 120° C., and preferablyalso being subjected to reduced pressure, e.g., 10-300 mbar_(abs). Whileinorganic sorbents can be useful, because they typically have highphysical strength, they generally require high temperature and pressurefor adsorption and/or desorption of a gaseous component. For thisreason, such sorbents are not preferred and are generally unsuitable forhousehold use or other applications under mild conditions. Activatedcarbon, e.g. DEA embedded activated carbon, can also be used. However,such sorbents are generally not sufficiently stable for a prolonged useand tend to degrade under room conditions after two months.

Preferred sorbents of this invention for adsorbing CO₂ are light andporous, solid particles or beads provided with an amine functionalityand having high surface areas per volume. Suitable particles includezeolites (also referred to as molecular sieves), ceramic basedmaterials, such as alumina, silica, and silica alumina, titaniumdioxide, silica gel, activated carbon and organic polymers, such aspolystyrene, modified by amines, such as Diethanolamine (DEA) orPolyethylenimine (PEI) or a divinylbenzene based amine orethylenediamine. More preferred are sorbents that can be readilyregenerated for reuse, particularly when recovering the adsorbed CO₂.For example, the sorbent can be an amine-modified particular material,based on cellulose, such as an amine-modified nanofibrilated celluloseas described in WO2014/170184 A1 and WO2010/091831 A1 or ion exchangeresins having benzyl amine groups as described in WO00/02643 A1.

Still more preferred for adsorping and desorping CO₂ are polymericsorbents having a primary amino functionality as described inWO2016/037688 A1 Even more preferred as sorbent is a free base aminebead functionalized with the primary amine benzyl amine and supported ona porous polyester structure crosslinked with divinyl benzene,particularly a sorbent which is in the form of spherical beads ofpolystyrene, cross-linked with 8-10% divinyl benzene modified withmethylamine.

The polymeric sorbent preferably has an activity expressed as totalcapacity of at least 2 eq/l, more preferably at least 2.1 and yet morepreferably at least 2.2. It preferably has a uniformity coefficient ofat most 1.9, more preferably at most 1.8. A preferred sealable enclosure10 for the process and apparatus of this invention is shown in FIGS.1-9.

As particularly seen from FIGS. 1-4, the sealable enclosure 10 has avacuum chamber 12 with an inlet 14 for a raw gas stream and an outlet 16for a purified gas stream on its opposite axial walls 10A and 108respectively. The inlet 14 and outlet 16 are provided with conventionalsealable valve mechanisms 18 and 20, respectively, such as for instanceconventional butterfly valves. A conventional compressor or fan,preferably just a fan 19, is connected to the sealable valve mechanism18 to provide a flow of a gas stream, preferably air, into the vacuumchamber 12 through its inlet 14. A conventional vacuum or extractionpump 21 is connected to the sealable valve mechanism 20 to remove a gas,preferably CO₂-depleted air and/or CO₂, from the vacuum chamber 12through its outlet 16. Preferably, the vacuum chamber 12 and its valvemechanisms 18 and 20 are vacuum tight. The vacuum chamber 12 of thesealable enclosure 10 contains one or more, preferably a plurality, morepreferably two, parallel, axially spaced-apart stacks 22 of cartridges24. Each stack contains a plurality of parallel adjacent,self-supporting, spaced-apart layers or cartridges, generally 24, asshown in FIGS. 2, 4, 8 and 9. Each stack 22 is preferably spaced awayfrom the lateral walls 10E and 10F of the vacuum chamber 12. Preferablyat least 10, more preferably at least 20, still more preferably at least25-40, cartridges 24 are provided between the inlet 14 and outlet 16 ofthe vacuum chamber 12. Each stack 22 preferably contains at least 10,more preferably 15 or more, cartridges are provided between the inletand outlet of the gas stream. The top wall 10C of the sealable enclosureis removable to allow for easy insertion of the stacks 22 of cartridges24.

Each cartridge 24 in each stack 22 in the vacuum chamber 12 has anessentially planar configuration and encloses a particulate sorbent (notshown) for a gaseous component (e.g., CO₂) of a raw gas stream inaccordance with this invention. Each cartridge 24 extends axially in thesealable enclosure 10, i.e., substantially parallel to the flow of thegas stream through the sealable enclosure between its inlet and outlet14, 18. Each cartridge also preferably extends vertically in thesealable enclosure 10, between its top and bottom walls 10C and 10Drespectively. If desired, each axially-extending cartridge 24 couldinstead extend laterally in a vertically-extending stack 22 (not shown).As shown in FIGS. 8 and 9, the preferred axially- andvertically-extending cartridges in each preferred laterally-extendingstack 22 are spaced laterally apart from one another, so as to formchannels 26 for the flow of gases through the sealable enclosure Spacers(not shown) can be provided between the cartridges to ensure that thechannels 26 remain open during the process of this invention.Preferably, the cartridges are separated from each other by 0.3-0.7 cm,especially 0.4-4 cm to adequately keep open the channels 26.

Each cartridge 24, as shown in FIGS. 5-7, includes an axially-extendingand vertically-extending, substantially flat, stiff frame 30 which isopen at its lateral and vertical middle and which preferably has arectangular, particularly square, shape. Each frame 30 is made from astiff, mechanically stable, lightweight material, preferably a plastic.The size and shape of each frame 30 preferably is somewhat smaller thanthe lateral cross-section of the sealable enclosure 10, so that thechannels 26 are open adjacent the top and bottom walls 10C and 100 andthe opposite lateral walls 10E and 10F of the sealable enclosure. Eachframe 30 can be constructed from two identical, substantially flat,stiff frame members 32 which are open at their axial and horizontal orvertical, preferably vertical, middle and which have the shape of theframe. The frame members 32 can be attached to one another to form theframe 30 in a conventional manner, e.g., by adhesively bonding orwelding them together. Preferably, each frame member 32 has a pluralityof reinforcing ribs 34 extending across the open portions of the frameand attached to its opposite sides. As shown in FIGS. 5 and 7, a pair ofribs 34 preferably extend diagonally across each frame member 32 fromthe corners of the frame, and these ribs are attached to each otherwhere they cross. Each cartridge 24 has a cavity 36 within the openportions of its frame 30, between its frame members 32, which can hold ameasured quantity of the sorbent (not shown). For this purpose, thesorbent can be enclosed in a flexible fabric material (not shown) whichis gas permeable but impermeable to the sorbent. The top, bottom andaxial edges of this fabric enclosure for the sorbent can be attached toand held by, e.g., glued to, the frame 30, within its frame members 32.Thereby, the frame 30 can enclose the fabric and the sorbent heldtherein. The fabric enclosure for the sorbent can comprise anaxially-extending and vertically-extending fabric pouch or a singleaxially-extending sheet of fabric, folded along one side of thecartridge, or two substantially parallel axially-extending sheets offabric, forming the lateral sides of the cavity of the cartridge thatholds the sorbent. The flexible fabric can be a woven or nonwoventextile material, preferably based on polymeric fibers or yarns,particularly a woven fabric made from PET and/or PE fibers, or frommetal or metal alloy wires, such as typically employed for a metalmeshes. The reinforcing ribs 34 of the frame members 32 of each frame 30of each cartridge 24 are located on opposite lateral sides of the cavity36 and its fabric enclosure (not shown). Thereby, the reinforcing ribs34 can serve to maintain the essentially planar structure of eachcartridge 24 and keep its fabric enclosure from bulging laterallyoutward of the frame members 32 of the cartridge under the weight of thesorbent content of the cartridge.

The individual frame members 32 can be produced in a conventionalmanner, for example, by injection molding of a plastic material.Similarly, the frames 30 can be produced as one piece by injectionmolding a plastic material to a fabric which can form an enclosure for acavity 36 in the frame to hold a measured quantity of the sorbent. Inthis regard, a frame can be injection molded directly to the top, bottomand axial edges of a suitable fabric construction to form the enclosurefor the cavity 36 for holding the sorbent in the frame of a cartridge24. A suitable fabric construction could be: i) a fabric pouch or ii) asingle folded sheet of fabric with two substantially parallel, fabricportions or iii) two separate, substantially parallel, fabric sheets,each of which could form a fabric enclosure, forming a cavity 36 in theframe to hold the sorbent.

One or more cartridges 24, preferably all or most cartridges, arepreferably provided with a heat exchange element, preferably in the forma heating element 38. As shown in FIG. 6, the heating element 38 ispreferably a flat, electrical heating element extending across the openmiddle, preferably the axial and vertical middle, of the frame 30 of thecartridge. However, heat-exchange elements, connected to a waste heatrecovery system, could instead be provided in the cartridges.

One edge, preferably the top, of the frame 30 of each cartridge 24 ispreferably provided with one or more holes 40, into which loose sorbentparticles can be poured to fill the cavity 36 in the cartridge, formedby its fabric enclosure. Each hole 40 is adapted to be closed in aconventional manner, e.g., by heat-sealing a plug 42 in the hole, afterfilling the cartridge with the sorbent, in this regard, a sorbent ofthis invention preferably has good flowability properties for ease offilling each cartridge with sorbent through the holes 40. The vacuumchamber 12 of this invention features one or more laterally- orvertically-extending, preferably laterally-extending, stacks 22, eachcontaining a plurality of axially-extending cartridges 24 of thisinvention. The cartridges in each stack are laterally- orvertically-spaced apart, preferably laterally-spaced apart. As a result,a serpentine channel 26 is provided, extending through the stack(s) 22of cartridges 24 for the flow of a gas stream through the sealableenclosure. In this regard, each laterally- or vertically-spaced apart,preferably laterally-spaced apart, stack 22 preferably is laterally- orvertically-spaced way, preferably laterally-spaced away, from theadjacent, front and rear walls or top and bottom walls, preferably frontand rear walls 10E and 10F, of the vacuum chamber and is axially spacedaway from the opposite axial walls 10A and 108 of the vacuum chamber tomaximize the length of the serpentine gas flow channel 26. In apreferred vacuum chamber 12, pairs of axially-extending baffles 44 and46, respectively, are preferably provided adjacent to, and on laterallyopposite sides of, each of the inlet and outlet 14 and 16 of the vacuumchamber 12, and one or more laterally- and vertically-extending baffles48 and 49 are provided between the inlet and outlet 14 and 16. Thesebaffles 44, 46, 48 and 49 preferably extend vertically from the bottomwall 10D to the top wall 10C of the vacuum chamber 12 and provide aserpentine flow channel for movement of gas through the vacuum chamber.In this regard, the pair of baffles 44 direct movement of the initialgas stream from the inlet 14 toward the outlet 16 and also directmovement of a gas stream, from which a gaseous component, particularlyCO₂, has been partially removed, laterally away from the inlet 14. Thepair of baffles 46 direct movement of the final gas stream, from whichthe gaseous component has been removed, toward the outlet 16 and alsoprevent movement of gas, from which the gaseous component, has beenpartially removed, laterally toward, and outward of, the outlet 16. Thebaffles 48 and 49 channel gas, from which the gaseous component, hasbeen partially removed, laterally away from the inlet 14 in oppositelateral directions and laterally toward the outlet 16 in oppositelateral directions. A preferred vacuum chamber 12 with two or morelaterally-extending, stacks 22 of cartridges 24 preferably has a pair oflaterally- and vertically-extending baffles 48 and 49 on oppositelateral sides of the vacuum chamber 12, between each stack 22, tochannel movement of gas, from which the gaseous component, particularlyCO₂, has been partially removed, laterally within each stack and betweenthe adjacent stacks as shown in FIG. 9. An important advantage of thesealable enclosure 10 of this invention is that during adsorption of agaseous component, particularly CO₂, of a gas stream, the gas streamdiffuses into, rather than being forced through.

-   -   the cavity 36 of each cartridge 24 through its fabric enclosure,    -   then through the sorbent in the cavity of the cartridge, and    -   then out of the cavity of the cartridge through its fabric        enclosure.

Another advantage of the sealable enclosure 10 of this invention is thatits very thin cartridges 24 containing the particulate sorbent can bestacked in a relatively compact manner as shown in FIGS. 8-10, so thatthe length of the serpentine or zig-zag flow path of a gas streamthrough the sealable enclosure is large while the dimensions of thesealable enclosure are relatively small. For example, if 1 m³ of sorbentis provided in a single packed bed with a bed length of 1 cm, this willresult in a bed cross section area of 100 m². However if the same amountof material is arranged in 100 stacked layers, each of 1 cm thicknessand 1 m² area, with 1 cm wide inlet and outlet channels between them,this will result in overall stack dimensions of 1 m×1 m×2 m, which ismuch more compact and has therefore a much smaller footprint. At thesame time, the stacked arrangement significantly facilitates gasdistribution. While even distribution of a gas stream towards the bottomarea of a 100 m² large bed will require excessive ducting, the ductingrequired to guide a gas flow towards the inlet of a 1 m×1 m×2 m stackwill be relatively small. In this regard, the stacking of the cartridges24 to provide a serpentine flow path of a gas stream through thesealable enclosure produces a more uniform pressure gradient in thesealable enclosure. This results in a more uniform diffusion of the gasstream through the sorbent in the cartridges, which ensures the mostefficient utilization of the sorbent during the adsorption process. Infact, the diffusion of the gas stream along a serpentine flow path inaccordance with this invention provides a very low pressure drop systemwhich does not require pumping of the gas stream.

Still another advantage of the sealable enclosure 10 of this inventionis that due to the fact that that its cartridges 24 containing sorbentare stacked as individual layers (as opposed to prior art structuresthat are, for example, extruded or cast from a single material), thestack 22 of cartridges can be made from various materials and variousmaterial combinations. For instance, a frame 30 defining the geometry ofeach cartridge can be made from a stiff, mechanically stable,lightweight material, while the flexible fabric material enclosing thesorbent material layer can be made from a different material with thedesired permeability properties for the air flow and the sorbentmaterial particles. Likewise, the frame 30 and fabric enclosing thesorbent can be made from materials which compensate differently forchanges in temperature or pressure in the salable enclosure.

The sealable enclosure 10 of this invention can be used in a cyclicadsorption/-desorption process to: i) separate a desired gaseouscomponent, particularly CO₂, of a gas stream, particularly atmosphericor outdoor air, from the remainder of the gas stream, using aparticulate sorbent; and ii) subsequently desorp the desired gaseouscomponent from the sorbent and recover the desired gaseous component.During the adsorption step, the gas stream is forced by a compressor orfan, preferably a fan 19, to flow through the valve mechanisms 18 and 20at the inlet 14 and outlet 16 of the sealable enclosure and through itsvacuum chamber 12, preferably under ambient conditions, more preferablyat 20-40° C., and at 0.7 to 1.3 bar absolute pressure, whereby a portionof the desired gaseous component contained in the gas stream is bound atthe surface of the sorbent in the stack 22 of cartridges 24 in thevacuum chamber. During the subsequent desorption step, the flow of thegas stream through the sealable enclosure is stopped, and the sorbent inthe stack 22 of cartridges 24 is heated, preferably under mildconditions, more preferably up to 50 to 120° C., and is preferably alsosubjected to reduced pressure, preferably 10-300 mbar_(abs) by a vacuumpump 21. This provides a gas stream effluent from the sealable enclosurethat is highly concentrated in the desired gaseous component,particularly CO₂. Alternatively during the subsequent desorption step,the flow of the gas stream, particularly atmospheric air, through thesealable enclosure is continued, and the sorbent in the stack 22 ofcartridges 24 is heated, preferably under mild conditions, morepreferably up to 50 to 120° C. This provides a gas stream effluent fromthe sealable enclosure that is much less concentrated in the desiredgaseous component, particularly CO₂. Heating of the sorbent can becarried out in any conventional manner, such as by passing a heated airstream through the sorbent and the vacuum chamber 12. Preferably, thesorbent is heated by means of a heat exchange element, particularly theheating elements 38 in the cartridges 24.

The sealable enclosure 10 of FIGS. 1-9 is particularly well suited foruse in a process for separating and removing CO₂ from air in an enclosedor confined space, such as an office, a hotel room, an airplane, anautomobile, a truck, or a train carriage. This sealable enclosure 10 isalso particularly well suited for use in a process of removing CO₂ fromair and then providing the CO₂ in high concentration to enclosed orconfined spaces such as greenhouses (for enhancing plant growth) orvivaria, such as terraria and aquaria (for enhancing aquatic plantgrowth).

Accordingly, the present invention also relates to a process furthercomprising providing a stream essentially comprising of the first gasfrom the desorption process to a further process. Preferably, thefurther process comprises a chemical conversion process, a process forthe growth of plants, and/or a process for the carbonation of a fluid,such as a beverage, or an aquarium, or to chemical processes for theconversion of CO₂, such as hydrogenation methanol. Also relevant may bethe provision of CO₂ for as an inert gas, such as for food packagingpreservation, or green houses, or for the buffering of the pH of aqueousfluids. Hence, not only can the process and apparatus advantageously beemployed to remove a gas, preferably CO₂ from an enclosed or confinedspace, and thus increase the air quality in the space, but also oralternatively, the process and apparatus may also serve to supply thedesorped gas stream to an industrial process.

In this regard, a lower cost, alternative sealable enclosure 110 of thisinvention can be used in a somewhat different way to remove CO₂ fromoutdoor or atmospheric air and then provide a concentrated CO₂ gasstream to an enclosed or confined, interior space 150, such as in agreenhouse, as shown schematically in FIGS. 10A and 10B. (Referencenumbers are greater by 100 for elements of the sealable enclosure 110than are corresponding elements of the sealable enclosure 10 of FIGS.1-9.)

The sealable enclosure 110, like the sealable enclosure 10, has a vacuumchamber 112 with an inlet 114 for a gas stream and an outlet 116 for agas stream on opposite walls and one or more stacks 122 of a pluralityof cartridges or layers 124. The vacuum chamber 112 preferably need onlybe a hermetically sealed container. Between the cartridges 124 is aserpentine channel 126 for the flow of gas from the inlet 114 to theoutlet 116, with diffusion of the gas through a particulate sorbent (notshown) in a fabric enclosure (not shown) in each cartridge 124. Eachcartridge 124 has a stiff rectangular frame 130 (not shown) that issubstantially flat and open at its middle and is formed by two attached,identical, substantially flat and open, stiff frame members 132 (notshown) with the shape of the frame. Each frame member 132 has a pair ofreinforcing ribs 134 (not shown) extending diagonally across the framemember 132 from the corners of the frame member and being attached tothe corners of the frame member and to each other where the ribs 134cross. A flat, electrical heating element 138 (not shown) extends acrossthe open middle of the frame 130 of one or more, preferably all or most,of the cartridges 124 of the sealable enclosure 110

However, the vacuum chamber 112 of the sealable enclosure 110 of FIGS.10A and 108, unlike the vacuum chamber 12 of the sealable enclosure 10,need not be vacuum tight, and its upper and lower, valve mechanisms118A, 118B and 120A, 120B at its inlet 114 and outlet 116, respectivelyneed not be vacuum tight. The sealable enclosure 110 can be used to:

-   -   remove CO₂ from atmospheric or outdoor air by forcing the air,        with a fan 119 (not shown), into and through the open, lower        valve mechanisms 118B and 120E of the sealable enclosure 110, so        that the CO₂ is adsorbed on the sorbent of the cartridges 124 as        shown in FIG. 10B: in this step, movement of gas between the        sealable enclosure 110 and the space 150 of a building, such as        in a greenhouse, is prevented by the closed, upper valve        mechanisms 118A and 120A; and then    -   desorb the CO₂ on the sorbent of the cartridges by heating the        cartridges 124 and forcing, with a fan (not shown), the desorbed        CO₂ into and through the space 150 as shown in FIG. 10A; in this        step, movement of gas between the sealable enclosure 110 and the        space 150 is possible through the open, upper valve mechanisms        118A and 120A, and movement of gas between the sealable        enclosure 110 and atmospheric air is preferably prevented by the        open, lower valve mechanisms 118B and 120B; this provides a gas        stream effluent from the upper valve mechanism 120 of the        sealable enclosure that is more concentrated in CO₂ than is the        air in the space 150.

Another lower cost, alternative sealable enclosure 210 of this inventioncan be used in a somewhat different way to remove CO₂ from air in anenclosed or confined, interior space 250, particularly an apartment,office, car, truck, ship, airplane or bus, as shown schematically inFIGS. 11A and 118. (Reference numbers are greater by 200 for elements ofthe sealable enclosure 210 than are corresponding elements of thesealable enclosure 10 of FIGS. 1-9.)

The sealable enclosure 210, like the sealable enclosure 10, has a vacuumchamber 212 with an inlet 214 for a gas stream and an outlet 216 for agas stream on opposite walls and one or more stacks 222 of a pluralityof cartridges or layers 224. Between the cartridges 224 is a serpentinechannel 226 for the flow of gas from the inlet 214 to the outlet 216,with diffusion of the gas through a particulate sorbent (not shown) in afabric enclosure (not shown) in each cartridge 224. Each cartridge 224has a stiff rectangular frame 230 (not shown) that is substantially flatand open at its middle and is formed by two attached, identical,substantially flat and open, stiff frame members 232 (not shown) withthe shape of the frame. Each frame member 232 has a pair of reinforcingribs 234 (not shown) extending diagonally across the frame member 232from the corners of the frame member and being attached to the cornersof the frame member and to each other where the ribs 234 cross. A flat,electrical heating element 238 (not shown) extends across the openmiddle of the frame 230 of one or more: preferably all or most, of thecartridges 224 of the sealable enclosure 210

However, the vacuum chamber 212 of the sealable enclosure 210 of FIGS.11A and 118, unlike the vacuum chamber 12 of the sealable enclosure 10,need not be vacuum tight, and two (2) two-way valve mechanisms 218, 220have been provided at its inlet 214 and outlet 216, respectively, eachof which can allow communication between the sealable enclosure andeither the interior of the space 250 or the exterior of the space. Thesealable enclosure 210 can be used to:

-   -   remove CO₂ from the air in the space 250 of a vehicle by forcing        the air, with a fan 219 (not shown), into and through the valve        mechanisms 218, 220, opened to the space 250 and closed to the        exterior of the space, so that the CO₂ is adsorbed on the        sorbent of the cartridges 224 as shown in FIG. 11A; in this        step, movement of air between the sealable enclosure 210 and the        space 250 through the inlet 214 and outlet 216 is allowed by the        valve mechanisms 218, 220, but movement of outdoor air between        the exterior of the space 250 and the sealable enclosure 210        through the inlet 214 and outlet 216 is prevented by the valve        mechanisms 218, 220, and then    -   desorb the CO₂ on the sorbent of the cartridges by forcing, with        a fan (not shown), outdoor air, preferably heated, into and        through the valve mechanisms 218, 220, closed to the space 250        and opened to the exterior of the space through the cartridges        224, so that CO₂ is desorbed from the sorbent of the cartridges        224 as shown in FIG. 118; in this step, movement of air between        the sealable enclosure 210 and the interior of the space 250        through the inlet 214 and outlet 216 is prevented by the valve        mechanisms 218, 220, but movement of outdoor air between the        exterior of the space 250 and the sealable enclosure 210 through        the inlet 214 and outlet 216 is allowed by the valve mechanisms        218, 220; this provides a gas stream effluent from the sealable        enclosure 210 to the exterior of the space 250 that is        concentrated in CO₂, thereby regenerating the sorbent of the        cartridges 224 for reuse in removing CO₂ from the air in the        space 250.

Another lower cost, alternative sealable enclosure 310 of this inventioncan be used in a somewhat different way to remove CO₂ from air in anenclosed or confined, interior space 350, particularly an apartment,office, car, truck, ship, airplane or bus, as shown schematically inFIGS. 12A and 12B. (Reference numbers are greater by 300 for elements ofthe sealable enclosure 310 than are corresponding elements of thesealable enclosure 10 of FIGS. 1-9.)

The sealable enclosure 310, like the sealable enclosure 10, has a vacuumchamber 312 with an inlet 314 for a gas stream and an outlet 316 for agas stream on opposite walls and one or more stacks 322 of a pluralityof cartridges or layers 324. Between the cartridges 324 is a serpentinechannel 326 for the flow of gas from the inlet 314 to the outlet 316,with diffusion of the gas through a particulate sorbent (not shown) in afabric enclosure (not shown) in each cartridge 324. Each cartridge 324has a stiff rectangular frame 330 (not shown) that is substantially flatand open at its middle and is formed by two attached, identical,substantially flat and open, stiff frame members 332 (not shown) withthe shape of the frame. Each frame member 332 has a pair of reinforcingribs 334 (not shown) extending diagonally across the frame member 332from the corners of the frame member and being attached to the cornersof the frame member and to each other where the ribs 334 cross. A flat,electrical heating element 338 (not shown) extends across the openmiddle of the frame 330 of one or more, preferably all or most, of thecartridges 324 of the sealable enclosure 310

However, the vacuum chamber 312 of the sealable enclosure 310 of FIGS.12A and 12B, unlike the vacuum chamber 12 of the sealable enclosure 10,need not be vacuum tight. Also, the inlet 314 of the sealable enclosure310 is open only to the interior of the space 350, and a single two-wayvalve mechanism 320 has been provided at the outlet 316 of the sealableenclosure 310 which can allow communication between the sealableenclosure and either the interior of the space 350 or the exterior ofthe space. The sealable enclosure 310 can be used to:

-   -   remove CO₂ from the air in the space 350 of a vehicle by forcing        the air, with a fan 319 (not shown), through the open inlet 314        of the sealable enclosure 310, so that the CO₂ is adsorbed on        the sorbent of the cartridges 324 as shown in FIG. 12A; in this        step, movement of air between the sealable enclosure 310 and the        space 350 through the outlet 316 is allowed by the valve        mechanism 320, but movement of outdoor air between the exterior        of the space 350 and the sealable enclosure 310 through the        outlet 316 is prevented by the valve mechanism 320; and then    -   desorb the CO₂ on the sorbent of the cartridges by forcing, with        a fan (not shown), air, preferably heated, from the space 350        through the open inlet 314 of the sealable enclosure 310, so        that the CO₂ is desorbed from the sorbent of the cartridges 324        as shown in FIG. 12B: in this step, movement of air between the        sealable enclosure 310 and the space 350 through the outlet 316        is prevented by the valve mechanism 320, but movement of outdoor        air between the sealable enclosure 310 and the exterior of the        space 350 through the outlet 316 is allowed by the valve        mechanism 320: this provides a gas stream effluent from the        sealable enclosure 310 to the exterior of the space 350 that is        concentrated in CO₂, thereby regenerating the sorbent of the        cartridges 324 for reuse in removing CO₂ from the air in the        space 350.

The sealable enclosures 10, 110, 210, 310 of this invention can be usedin a process for separating and optionally recovering a gaseouscomponent (e.g., CO₂) from a gas stream, such as atmospheric or outdoorair or air inside a closed or confined, interior space such as in abuilding, e.g., in one or more rooms of a house or office building or ina greenhouse, or in a vehicle, e.g., a car, truck, airplane or bus, oran exhaust gas from a chemical (e.g., combustion) or biological process.The sealable enclosures 10, 110, 210, 310 can also be used in a processfor separating and recovering CO₂ from outdoor air, i.e. air exterior toa closed or confined, interior space, e.g., a greenhouse, or from air inthe closed or confined, interior space and providing the recovered CO;to the closed or confined space or venting it to the outdoors.

Of course, the sealable enclosures 10, 110, 210, 310 can also be used inother applications, such as for the separation of CO₂ from flue gases,exhaust gases, industrial waste gases or for the separation ofcomponents other than CO₂ from these or other gas streams. The sealableenclosures 10, 110, 210, 310 can be of particular value for supplying agaseous component, particularly CO₂, of a gas stream, particularlyatmospheric air, in varying concentrations (e.g., as a function of thedemand) to an enclosed space, such as a greenhouse, or for watertreatment, fish farms or urban farming. More than one of the sealableenclosures 10, 110, 210, 310 can be connected together and used incombination for various purposes.

1-26. (canceled)
 27. An apparatus for the separation of CO₂ from air bya cyclic adsorption/desorption process using a loose particulate sorbentfor CO₂ adsorption, wherein said apparatus has an inlet for a first gasstream and an outlet for a second gas stream, and wherein said inlet canbe in communication with an enclosed or confined space, and said outletcan be in communication with both an interior of said space and anexterior of said space; characterized by a first valve mechanism whichcan control said outlet to provide selective communication of saidoutlet with either said interior of said space or said exterior of saidspace.
 28. The apparatus of claim 27, wherein said first valve mechanismis a single two-way valve.
 29. The apparatus of claim 27, wherein saidinlet can be in communication with both said interior of said space andsaid exterior of said space, characterized by a second valve mechanismwhich controls said inlet to provide selective communication with eithersaid interior of said space or said exterior of said space.
 30. Theapparatus of claim 29, wherein second valve mechanism is a singletwo-way valve.
 31. The apparatus of claim 27, wherein said inlet can bein communication with only said interior of said space.